Guppy Girl is a superhero that Molly pretends to be in the Bubble Guppies episode "Super Guppies". Guppy Girl is the mentor of Bubble Boy and Bubble Baby and one of the three defenders of Big Bubble City, and also one of the two main stars of the comic book series The Super Adventures of Guppy Girl and Bubble Boy, which is where Molly got the inspiration to pretend to be like her.
Molly/Guppy Girl is voiced by Bailey Gambertoglio.
In the retelling of the comic book in the episode, Molly (aka Guppy Girl) works as the mayor of Big Bubble City. But when she hears trouble in town or hears her Bubble Phone go off, she becomes Guppy Girl and flies off to save the day with her sidekick, Bubble Boy. During one mission, Bubble Boy and Guppy Girl were tasked with stopping the smelliest and evilest villain to ever attack Big Bubble City, Sid Fishy, from filling a cloud full of a concoction called Stink Sauce in order to make the cloud rain Stink Sauce all over the city. However, Bubble Boy was caught and trapped by Sid Fishy's henchman, Orange Ruffy, when he tried to turn off the pump inside Sid Fishy's blimp. While Guppy Girl was sent plummeting down to the street after getting hit by one of Bubble Boy's super bubbles filled with Stink Sauce, however she managed to save her self by creating a giant drop of water. She soon spots a cardboard cut-out of her at the news and magazine stand where her sidekick works when not on superhero duty, and gets an idea. Soon, using the cut-out, she freed her sidekick while he trapped Sid and Ruffy in a super bubble and they hauled them off to Big Bubble City Jail while the blimp filled back up with Stink Sauce and was sent into the ocean by Guppy Girl.
Her next mission came around when she and Bubble Boy had to stop Miss Goo-Goo from turning everyone in Big Bubble City into babies. However, her sidekick was turned into a baby and she had to battle Miss Goo-Goo alone until her baby sister, Mia (aka Bubble Baby), came and helped save the day alongside her big sister.
- Its revealed her friend and secretary, Deema, is the only citizen in Big Bubble City that knows that Mayor Molly and Guppy Girl, as well as Mia and Bubble Baby, are one and the same.